The present invention is related to servo control systems, and more particularly to such systems useable in electronic transmission shaft speed control systems.
In electronic transmission control systems, particularly systems designated as synchronized transmission systems, such as U.S. Pat. No. 4,329,885, for example, it is known that implementing a specific gear coupling between a drive shaft and a driven shaft is best accomplished when these shafts are being synchronously rotated at the predetermined angular speeds of rotation which are to be implemented by the selective gear to be coupled therebetween. In other words, prior to implementing a gear driving coupling between a drive shaft and a driven shaft, control is implemented such that the shafts are already rotating at the desired relationship between the shafts prior to implementing the gear coupling therebetween. Such systems are sometimes referred to as synchronized transmission systems, and examples of such systems and the components thereof are illustrated in U.S. Pat. Nos. 3,478,851, 4,430,911, 4,495,837, 4,495,839 and 4,329,855, the disclosures of which are incorporated by reference.
In prior electronic transmission control systems, it has typically been a problem in rapidly having the drive and driven shafts obtain the desired speed relationship therebetween which is necessary prior to the implementation of the desired gear coupling between the two shafts. Typically either a slow rise time for controlling the increase of one of the shafts, a slow fall time for decreasing the angular speed of one of the shafts, or a substantial overshoot in obtaining the desired end steady state speed of one of the shafts was encountered. While various techniques were proposed to speed-up the transient response of the entire system while minimizing the amount of overshoot in shaft speed control, the proposed solutions were either complex, costly or did not provide a sufficiently rapid transient response.